1. Technical Field
The present invention relates to an impact abrasion testing machine for concrete hydraulics structures, and more particularly, to a rotary-drum hydraulic-impact abrasion testing machine.
2. Description of Related Art
Because there are many steep hillsides in Taiwan, the concrete hydraulics structures, such as spillways or sluiceways, are subject to attack, abrasion and erosion of torrent carried with gravel, cobbles and boulders caused by heavy rain or typhoon; that causes severe damage such as the delaminating of the surface and the exposure of the primary steel frame of the spillways or sluiceways, and then shortens the service time of those concrete hydraulics structures eventually.
According to the classification of ACI 210R-93, the erosions on the hydraulics structures include: cavitation erosion, abrasion erosion and chemical erosion. More clearly, scholars David Plum and Fang Xufei divide the erosions on the hydraulics structures to abrasive wear, solid particles erosion, abrasion caused by sharp edges of solid particles, and pre-erosion peeling. After understanding the various erosions on the hydraulics structures, the most important thing is how to carry out the optimization design for the hydraulics structures. In which, scholar Papenfus finds that the major factor for wear resistance of the hydraulics structures is the binding between hardness, aggregate and cement mortar of a concrete hydraulics structure. Thereafter, for increasing the wear resistance of the concrete hydraulics structure, both novice researchers and scholars make great efforts to study how to find an optimal mixing proportion for the hardness, the aggregate and the cement mortar of the concrete hydraulics structure.
Inheriting to above descriptions, when studying the optimal mixing proportion for the hardness, the aggregate and the cement mortar, the researchers must do a verification for that through abrasion testing, therefore the researchers are able to confirm the relationship between the mixing proportion of the hardness, the aggregate and the cement mortar and the wear resistance of the concrete hydraulics structure. According to the material testing methods provided by American Society for Testing Materials (ASTM), the abrasion testing methods for the concrete hydraulics structure include: sand blasting testing of C418, C779 testing method for abrasion resistance of horizontal concrete surfaces, rotational grinding testing of C994, and abrasion testing of C1138.
The abrasion testing ways of C418, C779 and C994 are all belong to dry abrasion testing way; However, because the surface layers of the hydraulics structures are always subject to grinding, scraping, cutting, rubbing, scouring, and impacting by the torrent carried with the gravel, the cobbles and the boulders, the erosions on the surface layers of the hydraulics structures are very complex. So that, the researchers commonly use the C1138 abrasion testing way to verify and simulate the erosions on the surface layers of the hydraulics structures caused by the colloids in water.
Please refer to FIG. 1, there is shown a cross-sectional view of a conventional C1138 abrasion testing machine. As shown in FIG. 1, the C1138 abrasion testing machine 1′ includes: a base 11′ and a barrel 12′, wherein the bottom of the barrel 12′ provided with a sample supporting framework 121′ bearing with a concrete sample 2′. When processing the abrasion testing, it needs to inject water into the barrel 12′ and next to put a plurality of steel balls 13′ with different sizes on the surface layer of the concrete sample 2′. Then, by operating a motor (not shown) to drive the shaft 14′ in the barrel 12′ to rotate, water current is resulted from the rotation of a plurality of mixing blade 15′. Thus, through the water current, the steel balls 13′ would move on the surface layer of the concrete sample 2′, so as to simulate the impact on the (concrete) hydraulics structure caused by the water containing sand.
According to above descriptions, it is able to know that the C1138 abrasion testing machine 1′ is a commonly-used abrasion testing machine for the hydraulics structures, and the testing time of the C1138 abrasion testing machine 1′ is at least 48 hr according to the specification of ASTM. However, when the C1138 abrasion testing machine 1′ is used to process the abrasion testing for a high-strength concrete, it cannot find any obvious divergences on the surface layer of the high-strength concrete under 48 hr testing time because the surface layer of the high-strength concrete has a better wear resistance; so that, 72 hr is an appropriated testing time for the high-strength concrete. Therefore, according to above descriptions, it is able to find that long testing time is the main shortcoming of the C1138 abrasion testing machine 1′. Moreover, since the erosions on the surface layers of the hydraulics structures caused by the water containing sand are very complex, the C1138 abrasion testing machine 1′ cannot completely simulate all natural erosions on the surface layers of the hydraulics structures; That is another drawback of the C1138 abrasion testing machine 1′.
Accordingly, in view of the conventional C1138 abrasion testing machine still having shortcomings and drawbacks, the inventor of the present application has made great efforts to make inventive research thereon and eventually provided a rotary-drum hydraulic-impact abrasion testing machine.